When you enter Route 3 your friends will talk among themselves. After the conversation, you will obtain the Adventure Rules item. This is a little book with a few basic rules on playing Pokemon. Further ahead are more Pokemon Trainers around the tall grass.

A ledge is located further south. If you jump down this ledge, you won't be able to climb back up. Don't worry, you can walk around the tall grass to return to the northern part of this route. Further south is a Super Potion. West of the item is another Pokemon Trainer.